Idler shaft extremely hot

[Majones1]

Before powering up the 1955 Mark 5 I received from MickyD last weekend I removed the belt cover and headstock’s rear access cover to clean out the headstock and check things out. I put a few drops of oil in the hole on the lower sheave, powered it up and turned it up to jigsaw speed and back down a couple of times, to hopefully spread the oil a little bit. I then powered it up long enough to run the speed up to O or P, turned it off and lubricated both upper and lower sheaves, then powered it up and ran it down to slow and back up to O or P a couple of times, powered it off, put a few more drops of oil on both sheaves, and then ran the speed down, up and and back down to slow before turning it off again. When I touched the cap on the idler shaft it was extremely hot.

When I first turned the Mark 5 on it was very loud, vibrated and shook a lot, and the speed control dial was very sluggish. Oiling the sheaves made it a little easier to turn, but in the end it was still very hard to turn. I went slow and careful but I’m afraid of damaging it. I’m going to get the recommended dry lubricant tomorrow for it tomorrow, but I don’t think that’s going to completely fix its sluggishness.

I’m looking for your advice on what I should do here. My inclination is to take it apart, do some cleaning, and check the bearings.I re-read MickyD’s description of the work he did on the components in the Idler sub-section and everything looks clean. Mike did a great job cleaning but I suspect the bearings are very stiff, at a minimum. Looking at his photos it looks like the unit has the newer version of idler shaft, with the dual bearings, but he did not replace them. I know he received the SS in pretty bad condition and did a superb job of reconditioning everything, but I’m thinking that since it had now sat for a few years again, im suspecting that I need to check the bearings and be ready to change them.

Note that my model does have a Gilmer belt and not the Poly-V. Everything else, besides the idler shaft, is running cool. But this Mark 5 is at least twice, and maybe three times as loud as my 10ER. I know my 10ER made quite a racket when I first got it, but after I replaced the drive shaft and variable speed changer’s oilite bearings, and the driveshaft pulley, that 10ER is very, very quiet now. I was shocked at how loud the Mark 5 is. Thanks in advance for your advice on what I should do here.

[JPG]

"extremely hot" Subjective. Uncomfortable or TOO hot to "keep" touching it?

Yes an M5 is quite 'noisy'. Initial vibration may be due to belt "set". Belt dressing will help that. Also excessive Gilmer belt tension can create vibration.

[chapmanruss]

Belt tension could cause the problem but I am inclined to suspect the bearings may be the cause. Removing the Idler assembly from the headstock will allow you to examine the condition of the bearings. If it doesn't turn freely than they should be replaced. Bad bearings will not only create heat but also rob power getting to the quill.

[Majones1]

Thank you for your your suggestions on my idler bearing heating problem. I’ve taken it apart and found it does not spin freely so I ordered a new shaft and eccentric from ShopSmith, and it shipped this morning. I thought my unit had the newer dual bearing shaft but it did not, it’s the older version so I had to change the eccentric too.

I think the quill bearing probably needs to be replaced, because it sounds like loose bearings when I hand rotate it, and I would like to change it to a dual bearing quill, but I don’t want to spend the money right now to change everything else that would be required to make a new quill work (meaning, changing from my gilmer drive to the poly-v). So that will have to wait a little bit.

I’m also changing the drive belt because the one I have is chewed up a bit. Belt dressing did quiet things down quite a bit, but since I’ll have things apart I figured I would go ahead and change it. The gilmer belt looks new. I had been wondering how there had been no discussion of the difficulty I’ve been having getting the speed control unit, quadrant, installed back into the headstock without the idler sheave blocking things and causing the drive belt to get pinched as i tightened things down. It seemed like a bad design, or I was missing something. Last night I was watching a ShopSmith video on changing the drive belt and learned an important step! The trainer showed how to pull the sliding sheave away from the motor to loosen and remove the drive belt!!! Without that belt blocking sliding sheave on the idler shaft, I should be able to fully close those sheaves and allow the speed control to be easily installed, and therefore not end up damaging the drive belt in the process. It looks to me like someone else had the same problem before I got this Mark 5 because that belt was already chewed up.

New tricks learned daily!!! I’m ready to get this thing working even better than when I received it. Like I told MickyD last week, I look at ShopSmith ownership like I do camping.. leave it better than you found it.

[ShoptimusPrime]

For rough or sluggish bearings that have sat for a long time, I've had great success in reconditioning them. You can use the same sewing machine oil used on the sheaves to try and get them to move freely again. Just put the bearings horizontal (flat) and put a few drops on the shield. The oil should flow into the very thin spaces and then after a while turn the bearing on its side and slowly start to work the oil around. I've been able to bring completely frozen bearings back to life this way on the idler shaft, quill, and drive shafts. If you don't want to completely disassemble your headstock, I do this on all of my cleaning sessions. Put it in drill press mode and take off the belt cover and oil the bearings you can easily get to. For the quill, take it out completely disassemble, clean and polish, the main quill tube. And while you're doing this put the quill shaft vertical in a piece of wood and let a few drops of oil soak into the single bearing.

You can even repack so called sealed bearings by "blowing" new grease into them. After you get the bearings moving well again. Take a piece of PVC pipe close (smaller) to the bearing size you have, and slowly heat it up with a heat gun till it is soft and pliable. Then quickly force it over the bearing and wait for it to cool. You now have an air tight outer seal. All you do now is load up the top of the bearing with new grease, plug up the inner hole of the bearing, if needed, and then blow into the pipe or use an air compressor. And repeat till satisfied. Doing this can push out the older grease as well. I like to run the bearings after this step against an old buffing wheel on a drill to work out any excess oil before reinstalling in the machine.

I may have to do a write up on this process in the future.

I never toss bearings, they can most of the time be saved or reused. If they are toast or grinding then they need to be replaced. But I like to try to save them first.

You may want to pick up a digital tach and horseshoe clip pliers at harbor freight and completely disassemble your speed control assembly. I polish the headstock where the dial rides/rubs, and the back of the dial to a mirror finish and then buff with jpw. Take out the center post where the worm gear is and clean that well. Might also polish that shaft and put a drop of oil inside the oil bearing before reinstalling it. Sometimes sawdust will pack behind the little gear that turns the dial and all this combined can make for a sluggish speed control and a very loud machine.

I agree with your mindset, leave it better than you found it. Someone told me once that a craftsman never really owns his tools. They are a caretaker of them to be passed down to the next generation.

[Majones1]

For rough or sluggish bearings that have sat for a long time, I've had great success in reconditioning them.
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I never toss bearings, they can most of the time be saved or reused. If they are toast or grinding then they need to be replaced. But I like to try to save them first.
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I agree with your mindset, leave it better than you found it. Someone told me once that a craftsman never really owns his tools. They are a caretaker of them to be passed down to the next generation.

Thanks for your great ideas. Because of this Mark 5's age, and since I have some knowledge of the state it was in prior to MickyD performing his wonderful recovery work on it, I have a belief that it may be best to replace these bearings. I could certainly be mistaken, especially since I can't see inside the bearings to know what's in there. My thought is that I don't want to be spending more time tearing the headstock apart too often, since I want to making sawdust instead, and that replacing the bearings will put the Mark 5 on track for another 66 years of enjoyable use.

I like your method of repacking the bearings. Many years ago, when I was in high school, I worked in the only full service gas station in my small country town, and I remember being taught by our mechanic how to repack bearings by just putting a wad of grease in the palm of my hand and pressing the edge of the bearing into that wad to press grease in between the races. It would be nice to be able to that with sealed bearings.

[DLB]

There are many approaches to bearings. I have a bias favoring sealed bearings over shielded, especially for the conventional headstock. Because it is forced-air cooled it pulls in a lot of dust and contaminants. I was told be a bearing guy that RS (sealed) bearings are much preferred in a dirty/dusty environment over shielded except in case of a high speed application. So in most cases if I have a bad bearing I replace it with the sealed version. IIUC most sealed bearing failures occur after the seal is no more, because contaminants can then enter and lubricant can then exit. I'm not aware of any way to restore the seal except to replace the bearing.

Shopsmith seems to be going in the opposite direction. (I'm not suggesting that is wrong, it's just an observation.) When I bought my PowerPro DIY kit I only observed one sealed bearing, the outer bearing in the quill. I did not see the motor bearings. The other five bearings were all shielded. The idler bearings are pretty fast, I don't think there is a RS option there. The PowerPro is not, IMO, forced-air cooled. There is a fan, but no clear airflow path. It's more of an air-movement approach, with precious little of that at low speeds. But I'd still choose sealed bearings where possible.

- David

[Majones1]

Yesterday I received a new idler shaft with dual pulleys on it, which meant I had to replace the eccentric bushing too. I also replaced my old drive belt with a new ShopSmith belt. After I got everything back together this evening I powered it up at Slow and let it run for a few minutes, just listening to it. It was quiet. Powered it off and, although it’s a little harder to turn manually, which I attribute to the new belt, everything appeared to be fine, so I started it up again. I slowly ran it up to “R” and then back down to slow, pausing to listen to it at a few points along the way. The continuous run time was about 5 minutes. After turning it off, I found I was able to grab the exposed idler shaft and hold on to it. Yes it was hot, but before I changed the shaft I couldn’t touch that shaft for more than a couple of seconds.

Did I say it runs a lot quieter? It’s not as quiet as my 10ER, but certainly better than before. This makes me very happy. I’m ready to make some sawdust!

Here’s a look at my old and new belts.

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Old drive belt, a little frayed.

B12442FD-DE30-4996-828E-C2AF9CD84EC7.jpeg (481.25 KiB) Viewed 1190 times

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New drive belt, a little shorter (not stretched)

E5A00538-526C-4FD0-BC89-3EEB80E1C018.jpeg (390.28 KiB) Viewed 1190 times

[JPG]

Yes, less frayed(and a bit shorter and a bit narrower).

Short causes it to run slower.

Narrow causes it to run faster.

Narrow can cause it to jam quicker.

Suggest you get the SS version.

It 'should' be 26 1/2" and a bit over 1/2".

[Majones1]

Suggest you get the SS version.

It 'should' be 26 1/2" and a bit over 1/2".

As I know you’ve seen in my post on the “Belts” thread, I did get this belt from SS, and it is slightly narrower than 1/2”. My measurement was after it was installed and had run for 5 minutes. I didn’t think to get measurements until after I read the previous discussion on getting a SS belt, and by then I had already installed it. I suppose that running it a bit and how tight it is since it is shorter could have some effect on width. I would expect the effect to be very minimal, but I don’t know what that means in terms of physical characteristics.

After I wrote my previous post I ran my Mk 5 for 12 minutes, with half of them being at a speed over J, and 2 of them at R. After stopping, I found that the idler shaft was very hot, but I was able to grab it and hold on. I couldn’t do that before changing the idler shaft, its bearings, and the drive belt. But now the top of the head stock also got a lot warmer, almost hot, which appears to have been caused by the drive shaft bearing heating up. Previously the headstock remained cool. I think this may be caused by the gilmer belt being too tight. I’ll adjust that and try this again.

I had adjusted the gilmer belt right after installing the new idler shaft, but before installing the new drive belt, and I suppose that the added tension of that belt could put more tension on the gilmer belt, since the idler shaft is only held in place at the one end. I would expect the design for that shaft to be solid enough to not allow very much displacement of the shaft as that would not be very good on the bearings. But the drive belt was much harder to roll onto the motor pulley because of the tension.

Another part of the problem with rolling the drive belt into the motor pulley was the belt got pinched between the sheaves of the idler pulley and I had to turn with the sanding disk to get things moving. It took maybe 1/8 turn of the sanding disk for the belt to get un-pinched and pop into place, and it never went to that depth again (keeping in mind that I never took the speed above R). Still, when the belt was pinched in the idler sheaves I was unable to turn the motor pulley to roll on the new, very tight drive belt.

I’ll adjust the gilmer belt and report back whether it solves my heating problem, and will document the speeds are I’m getting now.